Lubricant and/or coolant fluids are used for a variety of machining purposes, including cutting, drilling, sawing, and other processes involving friction and frictional heating between two or more bodies. Lubricant and/or coolant fluids commonly used for such processes are petroleum-based. Residue of these petroleum-based fluids must be removed using organic solvents such as petroleum distillates or chlorine solvents (e.g., 1,1,1-trichloroethane or trichloroethylene). These solvents contaminate the environment and pose health and safety hazards.
Some water-soluble lubricants exist. See, for instance, U.S. Pat. No. 4,636,321 "Water Soluble Lubricants," Kipp et al., 1987. This patent discloses a blend of polyakylene gylcol polymer(s), ethoxylated carboxylic acid(s) or alcohol(s), complex organic phosphate ester(s), alkanolamine(s), and water as a lubricant for high-pressure applications such as cold rolling of metals. Currently available water-soluble lubricants are generally costly to produce and still pose health and safety hazards.
The taxonomic family Malvaceae includes those plants commonly referred to as the mallow family. The origin of this family is probably Africa or Asia, and certain members have been cultivated since the 12th century BC. In addition to ornamental varieties, such as ornamental hibiscus, the Malvaceae family includes both cotton (grown for fibers from its seed head or boll) and okra. Okra (Abelmoschus esculentus (Hibiscus esculentus)) is a tropical plant grown extensively for the food value of its seedpods. The pods, which are harvested while immature and tender, are used for a variety of culinary purposes. Texas, Georgia, Florida, California, Tennessee, and Alabama are major okra-producing states in the U.S.
Plants in the family Malvaceae have been used in home medicine for many years. For instance, the leaves of Hibiscus rosa-sinesis L. (Shimizu et al. (1993) Biol. Pharm. Bull. 16(8):735-739) and flower buds from Hibiscus syriacus L. (Tomoda and Ichikawa (1987) Chem. Pharm. Bull. 35(6):2360-2365) have been used as treatments for various medical conditions. It is thought that the medical properties of these tissues might be conferred by the copious mucilages found in these and related plants. Recent studies have examined and compared the mucilages found in the tissues of several Malvaceae species (Tomoda et al. (1989) Carbo. Res. 190:323-328), as well as the tissues of plants beyond the Malvaceae family (Yamada et al. (1985) Carbo. Res. 144: 101-111). These studies focus on the anti-complementary activity of the polysaccharides found in these mucilages.
Highly purified okra polysaccharide has been used to enhance cardiac output (U.S. Pat. No. 4,154,822 "Polysaccharide for Enhancement of Cardiac Output," Poimeni et al., 1979). This patent discloses using a highly purified polysaccharide from okra pod tissue to modify the fluidity of blood in vivo, thereby providing increased blood flow through the heart. It was proposed that this medical property was the result of chemical interactions between blood cells and the extended, highly purified, substantially linear polysaccharide when it was suspended in blood.
Common flax (Linum usitatissumum) is a member of the flax family, grown extensively for the production of linen fibers (from the stem) and linseed oil (from the seeds). Flax fiber has been used for cloth for nearly 10,000 years; flax has been grown for linen in North America since at least as early as 1626. In the late 1800's, cotton replaced linen as the preferred clothing-fiber source in North America, and since then flax has been cultivated in the United States mainly for its seed. Though flax probably originated and can be grown in tropical climates, seed crops are better in cooler climates. Generally, flaxseed is first processed to harvest linseed oil (30-40% by weight), leaving linseed meal. This product contains 30-40% crude protein, and is valuable as feed for livestock. Linseed oil is used in the manufacture of paints, vanishes, linoleum, oilcloth, printing inks, and soaps, as well as to seal concrete pavements and other structures.
Particularly desirable would be lubricant and/or coolant fluids that could be removed using water and that would be non-toxic, biodegradable, environmentally benign, and readily available from a renewable resource. It also would be advantageous if the lubricant could be reclaimed/recycled for repeated use.